
/**
 * Loads a Wavefront .mtl file specifying materials
 */
import * as THREE from 'three';

export default class MTLLoader extends THREE.Loader {

  constructor( manager ) {

    super( manager );

  }
  /**
   * Loads and parses a MTL asset from a URL.
   *
   * @param {String} url - URL to the MTL file.
   * @param {Function} [onLoad] - Callback invoked with the loaded object.
   * @param {Function} [onProgress] - Callback for download progress.
   * @param {Function} [onError] - Callback for download errors.
   *
   * @see setPath setResourcePath
   *
   * @note In order for relative texture references to resolve correctly
   * you must call setResourcePath() explicitly prior to load.
   */

  load( url, onLoad, onProgress, onError ) {

    const scope = this;
    const path = this.path === '' ? THREE.LoaderUtils.extractUrlBase( url ) : this.path;
    const loader = new THREE.FileLoader( this.manager );
    loader.setPath( this.path );
    loader.setRequestHeader( this.requestHeader );
    loader.setWithCredentials( this.withCredentials );
    loader.load( url, function ( text ) {

      try {

        onLoad( scope.parse( text, path ) );

      } catch ( e ) {

        if ( onError ) {

          onError( e );

        } else {

          console.error( e );

        }

        scope.manager.itemError( url );

      }

    }, onProgress, onError );

  }

  setMaterialOptions( value ) {

    this.materialOptions = value;
    return this;

  }
  /**
   * Parses a MTL file.
   *
   * @param {String} text - Content of MTL file
   * @return {MaterialCreator}
   *
   * @see setPath setResourcePath
   *
   * @note In order for relative texture references to resolve correctly
   * you must call setResourcePath() explicitly prior to parse.
   */

  parse( text, path ) {

    const lines = text.split( '\n' );
    let info = {};
    const delimiter_pattern = /\s+/;
    const materialsInfo = {};

    for ( let i = 0; i < lines.length; i ++ ) {

      let line = lines[ i ];
      line = line.trim();

      if ( line.length === 0 || line.charAt( 0 ) === '#' ) {

        // Blank line or comment ignore
        continue;

      }

      const pos = line.indexOf( ' ' );
      let key = pos >= 0 ? line.substring( 0, pos ) : line;
      key = key.toLowerCase();
      let value = pos >= 0 ? line.substring( pos + 1 ) : '';
      value = value.trim();

      if ( key === 'newmtl' ) {

        // New material
        info = {
          name: value
        };
        materialsInfo[ value ] = info;

      } else {

        if ( key === 'ka' || key === 'kd' || key === 'ks' || key === 'ke' ) {

          const ss = value.split( delimiter_pattern, 3 );
          info[ key ] = [ parseFloat( ss[ 0 ] ), parseFloat( ss[ 1 ] ), parseFloat( ss[ 2 ] ) ];

        } else {

          info[ key ] = value;

        }

      }

    }

    const materialCreator = new MaterialCreator( this.resourcePath || path, this.materialOptions );
    materialCreator.setCrossOrigin( this.crossOrigin );
    materialCreator.setManager( this.manager );
    materialCreator.setMaterials( materialsInfo );
    return materialCreator;

  }

}
/**
 * Create a new MTLLoader.MaterialCreator
 * @param baseUrl - Url relative to which textures are loaded
 * @param options - Set of options on how to construct the materials
 *                  side: Which side to apply the material
 *                        THREE.FrontSide (default), THREE.BackSide, THREE.DoubleSide
 *                  wrap: What type of wrapping to apply for textures
 *                        THREE.RepeatWrapping (default), THREE.ClampToEdgeWrapping, THREE.MirroredRepeatWrapping
 *                  normalizeRGB: RGBs need to be normalized to 0-1 from 0-255
 *                                Default: false, assumed to be already normalized
 *                  ignoreZeroRGBs: Ignore values of RGBs (Ka,Kd,Ks) that are all 0's
 *                                  Default: false
 * @constructor
 */

class MaterialCreator {

  constructor( baseUrl = '', options = {} ) {

    this.baseUrl = baseUrl;
    this.options = options;
    this.materialsInfo = {};
    this.materials = {};
    this.materialsArray = [];
    this.nameLookup = {};
    this.crossOrigin = 'anonymous';
    this.side = this.options.side !== undefined ? this.options.side : THREE.FrontSide;
    this.wrap = this.options.wrap !== undefined ? this.options.wrap : THREE.RepeatWrapping;

  }

  setCrossOrigin( value ) {

    this.crossOrigin = value;
    return this;

  }

  setManager( value ) {

    this.manager = value;

  }

  setMaterials( materialsInfo ) {

    this.materialsInfo = this.convert( materialsInfo );
    this.materials = {};
    this.materialsArray = [];
    this.nameLookup = {};

  }

  convert( materialsInfo ) {

    if ( ! this.options ) return materialsInfo;
    const converted = {};

    for ( const mn in materialsInfo ) {

      // Convert materials info into normalized form based on options
      const mat = materialsInfo[ mn ];
      const covmat = {};
      converted[ mn ] = covmat;

      for ( const prop in mat ) {

        let save = true;
        let value = mat[ prop ];
        const lprop = prop.toLowerCase();

        switch ( lprop ) {

          case 'kd':
          case 'ka':
          case 'ks':
            // Diffuse color (color under white light) using RGB values
            if ( this.options && this.options.normalizeRGB ) {

              value = [ value[ 0 ] / 255, value[ 1 ] / 255, value[ 2 ] / 255 ];

            }

            if ( this.options && this.options.ignoreZeroRGBs ) {

              if ( value[ 0 ] === 0 && value[ 1 ] === 0 && value[ 2 ] === 0 ) {

                // ignore
                save = false;

              }

            }

            break;

          default:
            break;

        }

        if ( save ) {

          covmat[ lprop ] = value;

        }

      }

    }

    return converted;

  }

  preload() {

    for ( const mn in this.materialsInfo ) {

      this.create( mn );

    }

  }

  getIndex( materialName ) {

    return this.nameLookup[ materialName ];

  }

  getAsArray() {

    let index = 0;

    for ( const mn in this.materialsInfo ) {

      this.materialsArray[ index ] = this.create( mn );
      this.nameLookup[ mn ] = index;
      index ++;

    }

    return this.materialsArray;

  }

  create( materialName ) {

    if ( this.materials[ materialName ] === undefined ) {

      this.createMaterial_( materialName );

    }

    return this.materials[ materialName ];

  }

  createMaterial_( materialName ) {

    // Create material
    const scope = this;
    const mat = this.materialsInfo[ materialName ];
    const params = {
      name: materialName,
      side: this.side
    };

    function resolveURL( baseUrl, url ) {

      if ( typeof url !== 'string' || url === '' ) return ''; // Absolute URL

      if ( /^https?:\/\//i.test( url ) ) return url;
      return baseUrl + url;

    }

    function setMapForType( mapType, value ) {

      if ( params[ mapType ] ) return; // Keep the first encountered texture

      const texParams = scope.getTextureParams( value, params );
      const map = scope.loadTexture( resolveURL( scope.baseUrl, texParams.url ) );
      map.repeat.copy( texParams.scale );
      map.offset.copy( texParams.offset );
      map.wrapS = scope.wrap;
      map.wrapT = scope.wrap;
      params[ mapType ] = map;

    }

    for ( const prop in mat ) {

      const value = mat[ prop ];
      let n;
      if ( value === '' ) continue;

      switch ( prop.toLowerCase() ) {

        // Ns is material specular exponent
        case 'kd':
          // Diffuse color (color under white light) using RGB values
          params.color = new THREE.Color().fromArray( value );
          break;

        case 'ks':
          // Specular color (color when light is reflected from shiny surface) using RGB values
          params.specular = new THREE.Color().fromArray( value );
          break;

        case 'ke':
          // Emissive using RGB values
          params.emissive = new THREE.Color().fromArray( value );
          break;

        case 'map_kd':
          // Diffuse texture map
          setMapForType( 'map', value );
          break;

        case 'map_ks':
          // Specular map
          setMapForType( 'specularMap', value );
          break;

        case 'map_ke':
          // Emissive map
          setMapForType( 'emissiveMap', value );
          break;

        case 'norm':
          setMapForType( 'normalMap', value );
          break;

        case 'map_bump':
        case 'bump':
          // Bump texture map
          setMapForType( 'bumpMap', value );
          break;

        case 'map_d':
          // Alpha map
          setMapForType( 'alphaMap', value );
          params.transparent = true;
          break;

        case 'ns':
          // The specular exponent (defines the focus of the specular highlight)
          // A high exponent results in a tight, concentrated highlight. Ns values normally range from 0 to 1000.
          params.shininess = parseFloat( value );
          break;

        case 'd':
          n = parseFloat( value );

          if ( n < 1 ) {

            params.opacity = n;
            params.transparent = true;

          }

          break;

        case 'tr':
          n = parseFloat( value );
          if ( this.options && this.options.invertTrProperty ) n = 1 - n;

          if ( n > 0 ) {

            params.opacity = 1 - n;
            params.transparent = true;

          }

          break;

        default:
          break;

      }

    }

    this.materials[ materialName ] = new THREE.MeshPhongMaterial( params );
    return this.materials[ materialName ];

  }

  getTextureParams( value, matParams ) {

    const texParams = {
      scale: new THREE.Vector2( 1, 1 ),
      offset: new THREE.Vector2( 0, 0 )
    };
    const items = value.split( /\s+/ );
    let pos;
    pos = items.indexOf( '-bm' );

    if ( pos >= 0 ) {

      matParams.bumpScale = parseFloat( items[ pos + 1 ] );
      items.splice( pos, 2 );

    }

    pos = items.indexOf( '-s' );

    if ( pos >= 0 ) {

      texParams.scale.set( parseFloat( items[ pos + 1 ] ), parseFloat( items[ pos + 2 ] ) );
      items.splice( pos, 4 ); // we expect 3 parameters here!

    }

    pos = items.indexOf( '-o' );

    if ( pos >= 0 ) {

      texParams.offset.set( parseFloat( items[ pos + 1 ] ), parseFloat( items[ pos + 2 ] ) );
      items.splice( pos, 4 ); // we expect 3 parameters here!

    }

    texParams.url = items.join( ' ' ).trim();
    return texParams;

  }

  loadTexture( url, mapping, onLoad, onProgress, onError ) {

    const manager = this.manager !== undefined ? this.manager : THREE.DefaultLoadingManager;
    let loader = manager.getHandler( url );

    if ( loader === null ) {

      loader = new THREE.TextureLoader( manager );

    }

    if ( loader.setCrossOrigin ) loader.setCrossOrigin( this.crossOrigin );
    const texture = loader.load( url, onLoad, onProgress, onError );
    if ( mapping !== undefined ) texture.mapping = mapping;
    return texture;

  }

}